[PATCH v2 04/24] block: move drain outside of read-locked bdrv_inactivate_recurse()

[Fiona Ebner]

This is in preparation to mark bdrv_drained_begin() as GRAPH_UNLOCKED.

More granular draining is not trivially possible, because
bdrv_inactivate_recurse() can recursively call itself.

Signed-off-by: Fiona Ebner <f.eb...@proxmox.com>
---

Changes in v2:
* Don't use atomics to access bs->quiesce_counter.
* Use goto for error handling/cleanup in bdrv_inactivate().

 block.c | 25 ++++++++++++++++++-------
 1 file changed, 18 insertions(+), 7 deletions(-)

diff --git a/block.c b/block.c
index 3065d5c91e..fa55dfba68 100644
--- a/block.c
+++ b/block.c
@@ -6989,6 +6989,8 @@ bdrv_inactivate_recurse(BlockDriverState *bs, bool 
top_level)
 
     GLOBAL_STATE_CODE();
 
+    assert(bs->quiesce_counter > 0);
+
     if (!bs->drv) {
         return -ENOMEDIUM;
     }
@@ -7032,9 +7034,7 @@ bdrv_inactivate_recurse(BlockDriverState *bs, bool 
top_level)
         return -EPERM;
     }
 
-    bdrv_drained_begin(bs);
     bs->open_flags |= BDRV_O_INACTIVE;
-    bdrv_drained_end(bs);
 
     /*
      * Update permissions, they may differ for inactive nodes.
@@ -7059,20 +7059,26 @@ int bdrv_inactivate(BlockDriverState *bs, Error **errp)
     int ret;
 
     GLOBAL_STATE_CODE();
-    GRAPH_RDLOCK_GUARD_MAINLOOP();
+
+    bdrv_drain_all_begin();
+    bdrv_graph_rdlock_main_loop();
 
     if (bdrv_has_bds_parent(bs, true)) {
         error_setg(errp, "Node has active parent node");
-        return -EPERM;
+        ret = -EPERM;
+        goto out;
     }
 
     ret = bdrv_inactivate_recurse(bs, true);
     if (ret < 0) {
         error_setg_errno(errp, -ret, "Failed to inactivate node");
-        return ret;
+        goto out;
     }
 
-    return 0;
+out:
+    bdrv_graph_rdunlock_main_loop();
+    bdrv_drain_all_end();
+    return ret;
 }
 
 int bdrv_inactivate_all(void)
@@ -7082,7 +7088,9 @@ int bdrv_inactivate_all(void)
     int ret = 0;
 
     GLOBAL_STATE_CODE();
-    GRAPH_RDLOCK_GUARD_MAINLOOP();
+
+    bdrv_drain_all_begin();
+    bdrv_graph_rdlock_main_loop();
 
     for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
         /* Nodes with BDS parents are covered by recursion from the last
@@ -7098,6 +7106,9 @@ int bdrv_inactivate_all(void)
         }
     }
 
+    bdrv_graph_rdunlock_main_loop();
+    bdrv_drain_all_end();
+
     return ret;
 }
 
-- 
2.39.5